It is known to coat the cylinder bearing surface of a cast-aluminum engine block with an iron alloy by carrying out arc wire spraying. Known arc wire spraying processes include twin-wire arc spray (TWAS) process, in which two wires are fed to a spray head in such a manner that the electric current is transmitted across the wires.
Coatings may also be applied by means of plasma spraying, in which a metal powder or a filler wire are melted and nitrogen is fed to the material mixture by means of metallic nitrogen compounds in order to harden the coating.
Present-day internal combustion engines and the engine blocks thereof can be cast from a metal or light metal, e.g. aluminum, aluminum blocks in particular having an iron or metal coating on the cylinder bores thereof. The metal coating can be sprayed on by thermal processes. The processes mentioned above are known as thermal spraying processes. It is advantageous to coat the cylinder bores by means of the plasma spraying process because it is thus possible to produce a coating which has a positive effect on a reduced wear factor and on an increased service life of the engine combined with a relatively low oil consumption as compared with conventional linings provided by means of gray cast iron alloys.
Nevertheless, present-day engine blocks, which are produced for example from a light metal, still have linings made of cast iron metal alloys, for example made of a gray cast iron, such that for example considerable wear arises, for example in the top dead center region but also in other regions of the cylinder liner. If such wear arises, an attempt might be made to provide for repair measures, or to replace the damaged cylinder block; this is not only very costly, but can also have a disadvantageous effect on the entire drive train, since replacement components may not immediately harmonize with existing components and, in certain circumstances, protracted setting work is required.
US Patent Application US2011030663A1 teaches that effective and economical repair by means of thermal spraying may be complicated owing to the aluminum lip which abuts the axial end of the cylinder liner and owing to the region between the aluminum lip and the surface region on the cylinder liner to be coated. US2011030663A1 furthermore discloses that only the worn region of the cylinder running surface is machined with the hammer or percussion brush, in which case the adjacent regions would not be damaged or machined and would remain in the, for example, honed state. Regions comprising different materials are thus produced in the cylinder liner and make uniform machining more difficult.